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ConcepTest PowerPoints

Chapter 17

Physics: Principles with Applications, 6th edition

Giancoli

ConcepTest 17.1aConcepTest 17.1a Electric Potential Energy I Electric Potential Energy I 1) proton2) electron3) both feel the same force4) neither – there is no force5) they feel the same magnitude

force but opposite direction

E

electronelectron

protonproton

E

electronelectron

protonproton++

--

1) A 1) A protonproton and an and an electronelectron are in are in a constant electric field created a constant electric field created by oppositely charged plates. by oppositely charged plates. You release the You release the protonproton from from the the positivepositive side and the side and the electronelectron from the from the negativenegative side. side. Which feels the larger electric Which feels the larger electric force?force?

E

electronelectron

protonproton

E

electronelectron

protonproton++

--

1) proton2) electron3) both feel the same acceleration4) neither – there is no acceleration5) they feel the same magnitude

acceleration but opposite direction

2) A 2) A protonproton and an and an electronelectron are in are in a constant electric field created a constant electric field created by oppositely charged plates. by oppositely charged plates. You release the You release the protonproton from from the the positivepositive side and the side and the electronelectron from the from the negativenegative side. side. Which has the larger Which has the larger acceleration?acceleration?

ConcepTest 17.1bConcepTest 17.1b Electric Potential Energy II Electric Potential Energy II

E

electronelectron

protonproton

E

electronelectron

protonproton++

--

1) proton2) electron3) both acquire the same KE4) neither – there is no change of

KE5) they both acquire the same KE

but with opposite signs

ConcepTest 17.1cConcepTest 17.1c Electric Potential Energy III Electric Potential Energy III 3) A 3) A protonproton and an and an electronelectron are in are in

a constant electric field created a constant electric field created by oppositely charged plates. by oppositely charged plates. You release the You release the protonproton from from the the positivepositive side and the side and the electronelectron from the from the negativenegative side. side. When it strikes the opposite When it strikes the opposite plate, which one has more KE?plate, which one has more KE?

4) Which group of charges took more work to bring together from a very large initial distance apart?

+1

+1

+1

d d

d

+1+2d

Both took the same amount of work

ConcepTest 17.2ConcepTest 17.2 Work and Potential EnergyWork and Potential Energy

1) V > 0

2) V = 0

3) V < 0

AA BB

5) What is the electric 5) What is the electric potential at point A?potential at point A?

ConcepTest 17.3aConcepTest 17.3a Electric Potential IElectric Potential I

1) V > 0

2) V = 0

3) V < 0

AA BB

6) What is the electric 6) What is the electric potential at point B?potential at point B?

ConcepTest 17.3bConcepTest 17.3b Electric Potential IIElectric Potential II

7) Four point charges are 7) Four point charges are arranged at the corners of a arranged at the corners of a square. Find the square. Find the electric electric field field EE and the and the potential potential VV at at the the center of the squarecenter of the square..

1) E = 0 V = 0

2) E = 0 V 0

3) E 0 V 0

4) E 0 V = 0

5) E = V regardless of the value

--QQ

--QQ ++QQ

++QQ

ConcepTest 17.4ConcepTest 17.4 Hollywood SquareHollywood Square

8) 8) At which point At which point does does VV = 0? = 0?

1

3

2

4

+Q –Q

5 all of them

ConcepTest 17.5aConcepTest 17.5a Equipotential Surfaces IEquipotential Surfaces I

9) Which of these configurations gives V = 0 at all points on the x-axis?

4) all of the above 5) none of the above

1)

x

+2C

-2C

+1C

-1C2)

x

+2C

-1C

+1C

-2C3)

x

+2C

-1C

-2C

+1C

ConcepTest 17.5bConcepTest 17.5b Equipotential Surfaces IIEquipotential Surfaces II

10) Which of these configurations gives V = 0 at all points on the y-axis?

4) all of the above 5) none of the above

ConcepTest 17.5cConcepTest 17.5c Equipotential Surfaces IIIEquipotential Surfaces III

1)

x

+2C

-2C

+1C

-1C2)

x

+2C

-1C

+1C

-2C3)

x

+2C

-1C

-2C

+1C

11) Which two points have 11) Which two points have the the samesame potential? potential?

1) A and C

2) B and E

3) B and D

4) C and E

5) no pair

A

C

B DE Q

ConcepTest 17.6ConcepTest 17.6 Equipotential of Point ChargeEquipotential of Point Charge

12 ) Which requires the most work, to move a positive charge from P to points 1, 2, 3 or 4 ? All points are the same distance from P.

1) P 12) P 23) P 34) P 45) all require the same

amount of work

P1

23

E

4

ConcepTest 17.7aConcepTest 17.7a Work and Electric Potential IWork and Electric Potential I

13) Which requires zero work, to move a positive charge from P to points 1, 2, 3 or 4 ? All points are the same distance from P.

1) P 12) P 23) P 34) P 45) all require the same

amount of work

P1

23

E

4

ConcepTest 17.7bConcepTest 17.7b Work and Electric Potential IIWork and Electric Potential II

14) Capacitor 14) Capacitor CC11 is connected across is connected across

a battery of a battery of 5 V5 V. An identical . An identical capacitor capacitor CC22 is connected across a is connected across a

battery of battery of 10 V10 V. Which one has the . Which one has the most charge?most charge?

1) CC11

2) CC22

3) both have the same charge

4) it depends on other factors

+Q –Q

ConcepTest 17.8ConcepTest 17.8 CapacitorsCapacitors

1) increase the area of the platesincrease the area of the plates

2) decrease separation between the platesdecrease separation between the plates

3) decrease the area of the plates

4) either (1) or (2)

5) either (2) or (3)

15)What must be done to a 15)What must be done to a capacitor in order to capacitor in order to increase the amount of increase the amount of charge it can hold (for charge it can hold (for a constant voltage)?a constant voltage)?

+Q –Q

ConcepTest 17.9aConcepTest 17.9a Varying Capacitance IVarying Capacitance I

+Q –Q

16) A parallel-plate capacitor 16) A parallel-plate capacitor initially has a voltage of initially has a voltage of 400 V400 V and and stays connected to the stays connected to the batterybattery. If the plate spacing is . If the plate spacing is now now doubled,doubled, what happens? what happens?

1) the voltage decreasesthe voltage decreases

2) the voltage increasesthe voltage increases

3) the charge decreasesthe charge decreases

4) the charge increasesthe charge increases

5) both voltage and charge changeboth voltage and charge change

ConcepTest 17.9bConcepTest 17.9b Varying Capacitance IIVarying Capacitance II

17) A parallel-plate capacitor initially has 17) A parallel-plate capacitor initially has a potential difference of a potential difference of 400 V400 V and is and is then disconnected from the charging then disconnected from the charging battery. If the plate spacing is now battery. If the plate spacing is now doubleddoubled (without changing (without changing QQ), what ), what is the new value of the voltage?is the new value of the voltage?

1) 100 V100 V

2) 200 V200 V

3) 400 V

4) 800 V

5) 1600 V

+Q –Q

ConcepTest 17.9cConcepTest 17.9c Varying Capacitance IIIVarying Capacitance III